Analysis of bacterial diversity associated with polyketide synthase (PKS) gene in brackish metagenome of TsoKar Lake of Ladakh, India

Aim: To explore bacterial diversity associated to polyketide synthase (PKS) genes in the TsoKar brackish metagenome.Methodology: The metagenomic DNA of TsoKar water and sediment samples were isolated and amplified using pks specific degenerate primers. PCR amplified products were analysed using Ion Torrent PGM platform and revealed a total of 2,11,030 reads with 534 contigs and 55% of G+C content. The results of BLASTx was further analyzed for species diversity using MEGAN5 software. Results: Halomonas was found to be the dominant phyla followed by Cyanobium, Acinetobacter and Burkholderia, respectively, along with majority of uncultured microorganisms present in TsoKar metagenome. Since TsoKar is a brackish water lake, and brackish aquatic ecosystems are a major hub of diverse microbes was also revealed in this study. TsoKar metagenomic sequence with accession number SRR8381943 was deposited in SRA database. Interpretation: TsoKar Lake is considered as one of the most important biosphere reserves. The results of this study confirm that this unique niche harbors good bacterial diversity associated with polyketide synthase genes, which justifies the idea of bioprospecting such niches for the discovery of novel metabolites like antimicrobial compounds using next-generation sequencing approach

Simultaneous detection of strychnine and brucine in biological matrix by gas chromatography-mass spectroscopy.

A new gas chromatography-mass spectroscopy (GC-MS) method is being presented for the separation and detection of strychnine and brucine, alkaloids of Strychnos nux vomica in a single run. The analysis was carried out using 5% phenyl methyl silicone capillary column, electron impact ionization mode and quadrupole mass analyzer. The extracts of the exhibits were analyzed using the new method. The peaks of the two alkaloids were found to be well resolved, and there was clear separation between the two. The retention time and mass fragmentation pattern, base peaks, molecular peaks of strychnine and brucine standard/NIST library and crime case exhibits matched, establishing the presence of the two active principles of Strychnos nux vomica. The new method has the advantage of better separation of the two alkaloid peaks over the conventional GC-MS methods, and is useful for the identification and confirmation of Strychnos nux vomica constituents in biological matrices of poisoning cases that have ended in death.